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An experimental investigation of passenger car disc brake noise has been made using the double pulsed laser holographic technique, developed to allow simultaneous recording of three orthographic visual images of a vibrating brake system. Mechanical measurements of parameters such as disc surface strain, torque, pad deflections, pressure and noise complement the visual images for both continuous and intermittent brake noise and enable phase relationships of the component parts to be determined. Visual images of the vibrational characteristics of a noisy brake show the disc to be in a bending mode with diametral modes. The pad is seen to vibrate in a variety of modes such as bending, torsion and often a combination of both and that pad end flutter is shown to make a significant contribution to brake system noise.